The electron spin resonance spectra of the radical cations of <i>p‐</i>terphenyl, triphenylene and triptycene

Courtneidge, John L.; Davies, Alwyn G.; Mcguchan, D. C.

doi:10.1002/recl.19881070317

Cited by 19 publications

(4 citation statements)

References 27 publications

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“…According to this model, the contribution of HFC to the spin dynamics was calculated using the semiclassical approximation of the function G ( t ) as follows with field units for σ. where σ 2 is the second moment of the radical ion EPR spectrum (Δ H pp = 2σ) and γ = g β/ℏ is the electron gyromagnetic ratio. For reference, the σ values of the RA and RC of perdeuterated p TP were approximately 0.07 and 0.08 mT, respectively, as evaluated from the HFC data for the radical ions of the protiated compound. , In some cases, for the RIPs composed of radicals with resolved EPR spectra, analytical solutions, which can be found elsewhere, , were used.…”

Section: Materials and Methodsmentioning

confidence: 99%

“…For reference, the σ values of the RA and RC of perdeuterated pTP were approximately 0.07 and 0.08 mT, respectively, as evaluated from the HFC data for the radical ions of the protiated compound. 28,29 In some cases, for the RIPs composed of radicals with resolved EPR spectra, analytical solutions, which can be found elsewhere, 30,31 were used.…”

Section: Tr Mfe Backgroundmentioning

confidence: 99%

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Spin-Correlated Radical Ion Pairs Generated in Liquid Haloalkanes Using High-Energy Radiation

Borovkov

2018

J. Phys. Chem. B

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The probability of formation of spin-correlated secondary radical ion pairs (RIPs) in diluted solutions of charge acceptors in irradiated haloalkanes is believed to be extremely low due to the dissociative attachment of excess electrons to solvent molecules. Contrary to this, it has been found that spin-correlated RIPs can be formed upon irradiation in some liquid chloroalkanes with yield sufficient to observe the recombination fluorescence of the RIP's partners. This allowed the study of primary radical cations (RCs) as well as radical ionic states of molecules dissolved in haloalkanes using the method of time-resolved magnetic field effect (TR MFE) in radiation-induced fluorescence. With this method, the magnetic resonance characteristics of the solvent RCs in a series of liquid haloalkanes were examined for the first time. For the 1,2-dichloroethane RC, the rate of scavenging by solute molecules and the dominant mechanisms of paramagnetic relaxation were determined. Polysulfone and poly(ethyl methacrylate) were used to demonstrate that due to their high dissolving ability, chloroalkanes can be exploited as solvents to study the magnetic resonance characteristics of radical ionic states of polymeric molecules in solutions with the TR MFE method.

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Section: Materials and Methodsmentioning

confidence: 99%

Section: Tr Mfe Backgroundmentioning

confidence: 99%

Spin-Correlated Radical Ion Pairs Generated in Liquid Haloalkanes Using High-Energy Radiation

Borovkov

2018

J. Phys. Chem. B

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“…For pTP and pTP-d 14 radical cations the value σ c was put at 0.357 mT 39 and 0.074 mT, respectively. For the radical anions σ a was put at 0.332 mT 20,21,40 and 0.069 mT, respectively.…”

Section: ■ Appendix Bmentioning

confidence: 99%

“…The functions G B,0 ( t ) depend on the parameters of the radical cation ( c ) and anion ( a ) and these are described by the following expression: G normalB ( t ) = exp [ − ( γσ t ) 2 / 2 ] G 0 ( t ) = 1 3 false[ 1 + 2 ( 1 − ( γσ t ) 2 ) .25em exp [ − ( γσ t ) 2 / 2 ) ] where σ 2 is the second moment of the ESR spectrum of the studied radicals, and γ is the gyromagnetic ratio for the radicals. For p TP and p TP- d 14 radical cations the value σ c was put at 0.357 mT and 0.074 mT, respectively. For the radical anions σ a was put at 0.332 mT ,, and 0.069 mT, respectively.…”

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confidence: 99%

Measurement of the Relative Mobility of Geminate Ions in Ethereal Solutions of Aromatic Compounds Using the Fluorescence Response of the Solutions to Pulsed Irradiation

Borovkov

Ivanishko

2013

J. Phys. Chem. B

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This work examines the possibility of using the fluorescence response of irradiated solutions of luminophores and the effect of an external electric field on the fluorescence decay to determine the mobility of geminate radical ions when using aliphatic ethers as the solvents. As an example, p-terphenyl solutions were studied in a series of ethers (diethyl, dibutyl, methyl tert-butyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, eucalyptol, and 1,2-dimethoxyethane). Verification of the nature of the charge carriers in the irradiated solutions was made by means of the method of the time-resolved magnetic field effect in recombination fluorescence of spin-correlated radical ion pairs. It was found that at a p-terphenyl concentration of about 10 mM, the observed fluorescent response from the solutions, in most cases, was due to the recombination of radical ions formed from the aromatic solute. The relative mobility of p-terphenyl radical ions in ethers was estimated by using a stochastic computer simulation of the radiation spur composed of 4 primary ion pairs. The ions' mobility was found to be dependent on solvent viscosity in accordance with Walden's rule, with no noticeable effect of solvent polarity.

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The Retro–Diels–Alder Reaction PartI.CCDienophiles

Rickborn

1998

Organic Reactions

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The Diels–Alder (“DA”) reaction is so familiar to organic chemists that the retro‐Diels–Alder or retro‐diene reaction (hereafter “rDA”) requires no conceptual introduction. However, a working definition is needed to indicate the coverage of this review. The intent is to include all reported examples of the general skeletal process excluded in this chapter. Any of the atoms in the starting material (cycloadduct) may be carbon or heteroatom, and substituents on all positions are allowed. In addition, any bond order available to the element in any oxidation state is included, as well as bonding to non‐nearest neighbor atoms (bicyclics, etc.). The volume of literature required separation of this review into two parts. Part I covers all expelled C–C dienophiles, i.e. those reactions that generate a new carbon‐carbon double or triple bond in the dienophile that is formed. Part II, to appear later, covers those expelled dienophiles in which one or both atoms is a heteroatom. Certain specific topics are intentionally omitted. These are: rDA reactions invoked under mass spectral conditions; rDA reactions of polymeric substrates; Electrocyclic processes, some of which are arguably very similar to rDA reactions (these are not addressed unless needed for clarification of an rDA sequence); and a thorough discussion of homo‐rDA reactions. CAS‐Online searches resulted in ca. 1,300 references, of which ca. 900 proved pertinent to the rDA topic as defined and delimited above. Active literature searching was halted in April 1995, but occasional more recent articles are included. Over 2,500 pertinent references were eventually found. Most were obtained by perusal of primary literature (articles) and secondary sources (books and reviews). Computer based search success was limited mainly by the failure of authors or abstractors to key‐word this topic, an especially common occurrence when the expelled dienophile was a simple substance such as N 2 or CO 2 . Overall, approximately 3,500 books, chapters, reviews, articles, and abstracts were consulted in an effort to make this review as comprehensive as possible. This was done with the certainty that some pertinent literature would be missed, tempered by the view that these omissions are probably also lost to any future rational search method. Many secondary sources proved valuable not only for in‐depth discussion of certain rDA reaction types, but also for providing comparisons with related topics. To assist the reader, these secondary sources are referenced (alphabetically by first author within broad subject areas) with a title or brief note on the topic(s) addressed. The first group lists earlier reviews with primary focus on rDA reactions, followed by items of Historical/General Interest, reviews that deal with Experimental Methods, DA reactions (general and specific), reviews of Related Topics (these impinge in more or less significant ways on rDA reactions), and general treatments of Theory and Mechanism.

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The electron spin resonance spectra of the radical cations of p‐terphenyl, triphenylene and triptycene

Cited by 19 publications

References 27 publications

Spin-Correlated Radical Ion Pairs Generated in Liquid Haloalkanes Using High-Energy Radiation

Spin-Correlated Radical Ion Pairs Generated in Liquid Haloalkanes Using High-Energy Radiation

Measurement of the Relative Mobility of Geminate Ions in Ethereal Solutions of Aromatic Compounds Using the Fluorescence Response of the Solutions to Pulsed Irradiation

The Retro–Diels–Alder Reaction PartI.CCDienophiles

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